Doctor Chooper curing Sanji's blindness would actually be a great medical feat for the little guy.
It would have to happen sometime after the fight. I don't see Sanji and Chopper double teaming Queen, or Queen giving Chopper any time to develop something mid-battle.
A 2v2 fight like Usopp and Chopper fighting Mr. 4 and Merry Christmas is one way to get Chopper directly involved against Queen. Queen sent Page One and X-Drake after Sanji, he might have another flying six member to stop Chopper from interfering.